This is a proposal to explore in detail some new experiments showing that the loudness of a test tone can be significantly increased by prior sound stimulation in the contralateral ear. The proposed experiments fall into three classes: 1) psychophysical and 2) electrophysiological measures on a group of human subjects, and 3) electrophysiological studies on cats prepared for acute and chronic recording from auditory structures. Specific tests designed to settle whether production of the phenomenon requires activity in the olivocochlear bundle are described.